How five women in the spotlight stay fit—whether they're performing on stage or swimming for Olympic Gold

On training for the NYC Marathon in just eight weeks: "When I started, I could barely run three miles. After a month of the Jeff Galloway run-walk-run interval method—a free download for people with injuries or who are late to running—I could do 18 miles. Let me tell you, when you start to run 25 miles a week, you notice a tighter butt."

Celeb Body Transformations

Celeb Body Transformations

On staying "as loose as possible" while performing up to six nights a week: "I start on the stationary bike. Then, I lie on my stomach on a massage table, pushing into my palms or elbows to tone my shoulder blades in order to hold my neck—which is very long—while I sing. My physiotherapist makes sure my spine is aligned and my shoulder blades aren't stuck together."